Change to DifferentialEquations.jl

[ChrisRackauckas]

This implements #3 . I am not entirely sure if the tests cover this though?

[bstellato]

I am getting this error:

julia> using SwitchTimeOpt
INFO: Recompiling stale cache file /Users/sidereus/.julia/lib/v0.6/SwitchTimeOpt.ji for module SwitchTimeOpt.
INFO: Recompiling stale cache file /Users/sidereus/.julia/lib/v0.6/OrdinaryDiffEq.ji for module OrdinaryDiffEq.
WARNING: The call to compilecache failed to create a usable precompiled cache file for module OrdinaryDiffEq. Got:
WARNING: Module Iterators uuid did not match cache file.
ERROR: LoadError: Declaring __precompile__(true) is only allowed in module files being imported.
Stacktrace:
 [1] __precompile__(::Bool) at ./loading.jl:335
 [2] __precompile__() at ./loading.jl:331
 [3] include_from_node1(::String) at ./loading.jl:569
 [4] eval(::Module, ::Any) at ./boot.jl:235
 [5] _require(::Symbol) at ./loading.jl:483
 [6] require(::Symbol) at ./loading.jl:398
 [7] _include_from_serialized(::String) at ./loading.jl:157
 [8] _require_from_serialized(::Int64, ::Symbol, ::String, ::Bool) at ./loading.jl:200
 [9] _require(::Symbol) at ./loading.jl:457
 [10] require(::Symbol) at ./loading.jl:398
while loading /Users/sidereus/.julia/v0.6/OrdinaryDiffEq/src/OrdinaryDiffEq.jl, in expression starting on line 1

Do you happen to get the same?

[ChrisRackauckas]

You need to Pkg.update(). Iterators.jl was removed from all packages in Julia v0.6 because of JuliaLang/julia#21969 .